1. Field of the Invention
The invention relates in general to an electrical connector, and more particularly to an electrical connection socket structure to be connected to an inserted plug of a signal wire.
2. Description of the Related Art
A conventional electrical connector has to be connected to various different audio signal wires, such as those of a multi-channel speaker, an earphone, a microphone, and the like. So, the connector usually has multiple plugs to be connected to the above-mentioned apparatuses. However, each plug has to correspond to a signal wire of a specific apparatus and the connection fails if the plug is connected to the wrong signal wire.
In order to facilitate the usage of connection so that the user does not have to insert the plug into the correct hole, the manufacturer adds a switch device to the electrical connection socket structure. The switch device is triggered by the inserted plug of the signal wire, and a chipset on a motherboard is enabled to make a selection and a conversion so as to match with the type of the inserted plug. Thus, the user can build a connection without having to insert the plug into the correct hole.
Referring to FIG. 1, a conventional electrical connector includes a plastic base 10 and a plurality of switch devices. The plastic base 10 is formed with a plurality of holes 11 and a circumferential wall of the hole 11 is formed with a flange 12.
Each switch device corresponds to each hole and includes a first terminal 13 and a second terminal 20. The first terminal 13 includes an elastic arm 14 and an extension 15. The elastic arm 14 has one end fixed to the plastic base 10 and the other end formed with a plastic projection 18 by way of injection molding. The extension 15 with an inverse-L shape has a transversal portion 16 and a longitudinal portion 17. A distal end of the transversal portion 16 is also fixed to the plastic base 10 and in contact with the elastic arm 14. A distal end of the longitudinal portion 17 is formed with a pin protruding over the plastic base. The second terminal 20 has a longitudinal portion 21 and a contact sheet 22. The longitudinal portion 21, which is parallel to the longitudinal portion 17 of the first terminal 13, has a lower end formed with a pin protruding over the plastic base. The contact sheet 22 connected in perpendicular to an upper end of the longitudinal portion 21 corresponds to the elastic arm 14 of the first terminal 13 and is formed with a protruding contact point 23.
According to the above-mentioned structure, when a plug 25 for the signal wire is inserted for connection, the plug 25 pushes the plastic projection 18 to bend down the elastic arm 14 of the first terminal 13 and thus electrically connect the first terminal 13 to the second terminal 20, as shown in FIG. 2. Thus, the plug 25 for the signal wire is separated from the first terminal 13 through the plastic projection 18 even if the switch device is ON, such that the plug 25 still can be normally electrically connected to signal terminals (not shown).
The prior art structure has the following drawbacks.
1. A gap between the elastic arm 14 of the first terminal and the contact point 23 of the second terminal 20 is relatively large, as shown in FIG. 2. Thus, when the plug 25 is inserted for connection, the elastic arm 14 of the first terminal 13 is bent down to elastically contact the contact point 23 of the second terminal 20. The contact sheet 22 of the second terminal is not pressed down by a distance, so the frictional effect generated between the elastic arm 14 of the first terminal and the contact point 23 of the second terminal 20 is relatively small, and the oxidation layers on the elastic arm and the contact point cannot be removed.
2. The structure is manufactured by injection molding the plastic projection 18 on the first terminal, so the manufacturing processes are complicated and are not easy, and the throughput is low. Thus, the cost is increased because the metal terminal has to be put in the mold followed by the injection molding.
3. Because it is very difficult to directly mold the plastic projection 18 on the whole first terminal 13 by way of injection molding, the first terminal 13 has to be cut into the elastic arm 14 and the extension 15. Then, the plastic projection 18 is formed on the shorter elastic arm 14. Although the difficulty of injection molding can be reduced, the two members of the first terminal have to be assembled together. So, the manufacturing cost is increased.